As prior art, there is known a method for producing a high-bulk sheet wherein a fiber suspension containing an added wet paper strength agent is supplied from a paper-making material supply head onto a paper layer-forming belt to accumulate fibers on the paper layer-forming belt, a wet fiber sheet is formed, a suction box is used for dewatering of the fiber sheet, and then steam is injected from a steam-injecting nozzle onto the fiber sheet to impart a prescribed pattern to the fiber sheet (for example, Japanese Unexamined Patent Publication No. 2000-34690). By this method for producing a high-bulk sheet, it is possible to produce a high-bulk sheet with large thickness, high absorption, excellent softness and suitable sturdiness.